Conversion of emitted axionic dark matter to photons for non-rotating magnetized neutron stars

Abstract

We attempt to find the impact of a modified Tolman Oppenheimer Volkoff (TOV) system of equations on the luminosities of direct photons and axions for a specific axion mass in the presence of a magnetic field. We employ two different equation-of-states (EoSs), namely APR and FPS, to generate the profiles of mass and pressure for spherically symmetric and non-rotating neutron stars (NSs). We then compute the axions emission rates by the Cooper-pair-breaking and formation (PBF) process in the core using the NSCool code. We also examine the possibility of an axion-to-photon conversion in the magnetosphere of NSs. Furthermore, we investigate the impact of the magnetic field on the actual observables, such as the energy spectrum of axions and axion-converted photon flux for three different NSs. Our comparative study indicates that the axion energy spectrum and axion-converted photon flux change significantly due to an intense magnetic field.